Spool casting die and core structure



E AND CORE STRUCTURE June 16, 1959 Filed April 3, 1956 Unite StatesPatent SPOOL 'CASTING DIE AND CORE STRUCTURE Louis H. Morin, Bronx,N.Y., assignor to Coats & Clark Inc., New York, N.Y., a corporation ofDelaware Application April 3, 1956, Serial No. 575,739

16 Claims. (Cl. 18-42) This invention relates to the production of castor moulded spools. More particularly, the invention deals with a die andcore structure for producing products of the kind under consideration.Still more particularly, the invention deals with a novel type of corestructure, the same to facilitate free separation of the cores one fromthe other and from the cast or moulded product.

The novel features of the invention will be best understood from thefollowing description, when taken together with the accompanyingdrawing, in which certain embodiments of the invention are disclosedand, in which, the separate parts are designated by suitable referencecharacters in each of the views and, in which:

Fig; l is a diagrammatic sectional view of part of the die and coremechanism, including portions of associate parts for use in producingspools in accordance with the method, the several parts being shown inthe casting or moulding position, with the section through the corestaken on the line 11 of Fig. 3.

Fig. 1a is a detailed sectional view of a portion of one end of a spoolmade according to my invention.

Fig. 2 is an isomertric View of a core unit detached, with part of theconstruction broken away.

Fig. 3 is a cross-sectional view through an assemblage of two coreunits, taken substantially centrally of the core members or elements ofthe unit.

Fig. 4 is an inside perspective View of one of the core members orelements showing mainly a core finger thereof; and

Fig. 5 is a perspective detailed view of one of the core members orelements, including a base part, with a portion broken away.

In order to illustrate the die and core structure in assemblage forproduction of a spool, preferably a plastic spool, I have illustrated,somewhat diagrammatically in Fig. l of the drawing, the various die andcore parts and portions of associated parts in the closed or casting ormoulding position. In said figure, represents the face view of one partof a die, the dies being movable in planes perpendicular to the showingin the drawing. At 11 is indicated part of a transfer device, includinga tapered transfer pin l2. 13 represents the sprue or gate leading intodivided sprue passages 14 which extend to the rim forming cavities 15 ofthe dies to form the rims 16 of the resulting spool 17. The dies arealso fashioned to partially form the outer annular label retainingflanges 18 'upon the outer surface of the rims 16, a cavity 19 toreceive the pin 12 and a cavity 20 to mould a sleeve-like part 21 uponthe pin and also including runners 22, which extend to the wall of thespool 17 At 23 I have indicated a small portion of core slides foractuating core assemblages 24, each assemblage including a core unit 25.

Each assemblage 24 is of the same general construction and, for thisreason, the brief description of one will apply to the other and likereferences will identify like parts. 26 represents the outer cylinder orshell of the assemblage, 27 the inner cylinder or shell, adjacentsurfaces of the shells being shaped to form therebetween a water coolingjacket 28, through which cooling water may be ciroulated by pipes, oneof which is indicated at 29.

O or other sealing rings 30 are provided between adjacent surfaces ofthe shells 26 and 27 in order to seal the jacket 28. Supported withinthe inner shell of each;

assemblage is a core shell or liner 31, which has, at its inner end, anannular core portion 32 for forming an annular groove 33 in each rimportion 16 of the resulting spool and also to form the inner diameterportionof the annular rim 18, as will be apparent from a considerationof Fig. l of the drawing. The outer end portionofi. each core shell 31has a shoulder 34 which abuts the inner shell 27 for definitepositioning of the core end 32' in the cavity 15.

The core units 25 are arranged within the core shell or liners 31 and,here again, as each unit 25 is of the same construction, the briefdescription of one unit will apply to both. One of these units is shownin the isometric view of Fig. 2 detached and it will appear that eachunit 25 comprises an assemblage of four similar core members or elements35. Each element 35 comprises an-v eniarged base'portion 36 which isadapted to seat upon the end of the core shell or liner 31, as seen at37 in Fig. l of the drawing.

Extending from the base portion 36 is a long body portion 38; these bodyportions of the respective core members or elements define a cylinder,the bore of which is indicated at 39. The portions 38 terminate in whatmay be termed shoulders or ledges 44), from which extend core fingers 41of each element or member, as is indicated in Fig. 5 of the drawing,which are tapered from the shoulders 40 outwardly to the free endsthereof and which have smaller arcuate inner surfaces 42 than the largerarcuate outer surfaces 43, as will clearly appear from a considerationof Figs. 3 and 5 of the drawing. This construction forms on the lateralsides of each finger 41 contracted side walls 44 and 45, that is, eachsuch side wall is tapered from its outer to its inner end. Side walls 44and 45 are partly defined by longitudinally inclined, bevelled shoulders46 and 47, respectively. The shoulders 46 face radially outwardly;whereas, the shoulders '47 face radially inwardly and, assuming that asection were taken substantially centrally through the assemblage of thetwo core units, as is noted in Fig. 3 of the drawing, the inclination ofthe shoulders is such as to position the abutting shoulders 46 and 47substantially centrally with respect to the radial dimension of the coreportion of the assembled core units. These shoulders serve to positivelysupport the assembled core units to resist the pressure of injection ofthe moulding material which is pressure injected into the die cavitiesin forming the cylindrical portion of the spool 17 around the assem--bled core units, as clearly indicated in Fig. 1 of the draw-- ing. Itwill also be apparent that the end extremities of the fingers 41 of onecore unit terminate in spaced rela-- tion to the shoulders 4i) of theother core unit, as indicated at 41' in Fig. l of the drawing, in orderto form the end wall portions 48 at the ends of the spool, between whichend wall portions there would be openings equivalent in size to thecross-sectional area of the core fingers 41 of the opposed core unit.These portions are shown at the upper right of Fig. 1 and at the lowerleft in Fig. 1 in alinement with the walls 48.

Supported in the bores 39 are mounting end portions 49 of outwardlytapered core pins 50, which extend into the bore 51 formed by theassembled core units 25 and are arranged in spaced relation thereto soas to form the inner small diameter tubular portion 52 of the resultingspool. It is also preferred that, where the mounting portions 4? jointhe pins 50, the core pins are fashioned, as

cavities to form the inner annular label retaining flanges 55 at endportions of the spool. However, in some instances, these inner flanges55 are dispensed with.

Suitable shimmed shoulders 56 are provided in the base of the core unitsfor bringing abutting surfaces 50' of the core pins 50 into engagementwith each other. It will also appear that suitable keys,diagrammatically shown at 57 in Fig. 1 of the drawing, are employed toextend into the base portion 36 to control alinement of the two' coreunits one with respect to the other in movement of thecore units intoand out of the area of the die cavity, so as to remove the cast ormoulded spool 17 when the die parts are separated.

On completing this operation, the transfer device 11 is actuated to movethe cast or moulded spool, together with the gate portions 58 toatrimming station where these gate portions 58, as well as the sleeve 21and its gate extensions are trimmed from the spool, thus producing afinished end product preparatory for the mounting of thread thereon andapplication of end labels. In this last named operation, it will beapparent that means will be provided to strip the sleeve 21 from thetransfer pin 12, preparatory to returning the pin to the castingposition.

In the above described operation of separating the core units 25, itwill be apparent that this operation will be performed without exertingany stress or strain upon the cylindrical walls of the cast or mouldedspool by reason of the tapered wall structure of the separate core fingers 41 of each core member or element. In other words, the instant thereis any relative movement between the core units, the engaged surfaceswill become free for free travel of the core units to their fully openedposition. Again, in bringing the core units back into assembledrelationship, the widespread throats between adjacent surfaces of thecore fingers 41 of each member or element provide free entrance of thecontracted end portion of the core fingers 41 of the opposed elements,until such time as these elements are brought into snug and firmengagement with each other and, at this time, the shoulders 34 willserve to definitely check movement of the core units toward each other.

For purposes of description, the spool may be said to comprise an innercentral tubular portion and an outer barrel having the integral rimends. It will be noted, from a consideration of Fig. 3 of the drawing,that the shoulders 46 and 47 are preferably rounded to provide smoothaction in assembling and separating the core fingers, it beingunderstood, in this connection, that, when the core fingers are inclosed position within the die cavity, all surfaces of the core fingersare held in firm abutting engagement with each other.

It will appear, from a consideration of Fig. 1 of the drawing, that thebase part of each core unit fits snugly upon backing plates 59 which, inturn, abut the slides 23.

In the production of spools as disclosed, it will be apparent that, inusing thermoplastic materials, the materials are injected into thecavities of the dies and around the cores at high pressure at about20,000 pounds per square inch. This is essential by virtue of theextremely thin walls which are formed in the resulting spool product.This pressure is applied to the core fingers of the assembled cores andis taken up by the snug engagement and fitting of the fingers one withthe other and reinforced by the interengaging shoulders 46 and 47 onthese core fingers.

' After the spool product has been moulded in the die cavities, thecores are withdrawn and, in this operation, there normally develops asubstantial drag, which is obviated with my present construction byvirtue of the tapering mating surfaces of the core fingers whichprovides a more or less instantaneous relief as the cores are drawnapart. This method of procedure further eliminates wear upon the coreunits and eleminates the necessity of lubricating the units whichusually has been the practice, particularly where the drag prevailed.

It will also be apparent that the core slides are firmly backed by themeans for actuating the same, so as to positively resist axial stressesor strains upon the core units which would tend to separate the same,particularly in injection of the moulding material between adjacentsurfaces of the cores at the shoulders or ledges 40 in forming the endwall portions 48 of the resulting spool.

In the operation of the core assemblages, it will be apparent that eachcomplete assemblage is movable with the cores and moves with the coreslides. The particular couplings and mountings are purposely omitted tosimplify the present showing. In this movement, it will be apparent thatflexible tubing, not shown, is coupled with the pipes 29 to compensatefor movement of the core assemblages.

It will be apparent that, while the core units 25 are generally of likeconstruction, they are what might be termed left and right hand forproper fitting and, while in the accompanying drawing, each core unit isshown as comprising four core fingers, this is only by way ofillustrating a simple adaptation of the invention. The number of fingersemployed in each unit can be modified to suit the resulting product tobe attained.

By way of summary, the device of Fig. 2, identified as 25, is termed acore unit; it comprises a plurality of separate, abutting core membersor core elements 35, one of which is separately shown in Fig. 5. Thelower portion of the core unit of Fig. 2, identified by numerals 36 and38, is termed a base, and the upper portion comprises a plurality ofcore fingers 41. The core member or element 35 of Fig. 5 has a lowerportion, identified by numerals 36 and 38, which may be termed a baseportion or base part.

' It is to be noted that each core member 35 comprises a single integralpart and is replaceable in the core unit. The provision of the shouldersor ledges 46 and 47 on each core finger represents a simplifiedconstruction for enabling these fingers to engage the fingers of anopposite core unit. Also, each core member has, in the base portionthereof, an outer shoulder portion 37 and an inner shoulder portion 56which aid in supporting the core members in die casting position and inmoving them to and from die casting position.

This application is a continuation-in-part of copending applicationsSer. Nos. 363,364 and 486,664, filed June 22, 1953, and February 7,1955, respectively.

- Having fully described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A die and core structure for moulding spool bodies having a centraltubular portion, a barrel having enlarged rim ends, each rim end beingpartially defined by an annular groove, and circumferentially spaced endwalls integrally united with the carrel and central tubular portion,said structure comprising dies movable toward and from each other andincluding cavities partially forming the barrel and enlarged rim ends, apair of opposed core units movable toward and from each other at rightangles to the movement of the dies, each core unit comprising a group ofcircumferentially spaced, identical, integral core elements; each coreelement comprising a base portion at the inner end thereof, anintermediate body portion having an outer end, and a core fingerextending from said outer end of the body portion and terminating in afree end; said base and body portions of said group of core elementscollectively forming circumferentially continuous base and bodyportions, respectively, having a throughbore; said core fingers of saidgroup of cole elements having a circumferentially spaced disposition;the fingers of one core unit interfitting with the fingers of theopposed core unit in forming a circumferentially continuous core withinthe dies to partially form the barrel and central tubular portion of theresult ing spool, the core fingers of each unit tapering fi'om the bodyportion outwardly to the free end of the fingers, and said free end ofthe core fingers terminating short of the body portion of the opposedcore unit to form cavities defining the circumferentially spaced endwalls of the resulfing spool.

2. A structure as defined in claim 1, in which each finger of each ofthe core units includes, at one lateral side thereof, an inwardly facingshoulder and, at the other lateral side thereof, an outwardly facingshoulder.

3. A structure as defined in claim 2, in which the shoulders areinclined from inner to the outer free ends of the fingers, wherein theoutwardly facing shoulders of the fingers of one unit firmly engage theinwardly facing shoulders of the fingers of :a companion unit when theunits are in assembled relationship Within the die cavity.

4. A structure as defined in claim 3, wherein means is provided on innerand outer sides of said base portions for keying the core units tomaintain meshing alinement of the core units one with respect to theother.

5. A structure as defined in claim 4, wherein each core unit hasradially outwardly thereof inner and outer shells with a water jacketdisposed therebetween, means for circulating water through the waterjacket, a core shell encircling the body portion of each core unit, andsaid core shell including an annular core portion extending into theannular groove partially defining the enlarged rim end of the resultingspool.

6. A structure as defined in claim 5, wherein the annular core portionof each core shell, in conjunction with the die cavity, collectivelyform a cavity at the end of the rim for producing, on the resultingspood body, an annular outwardly projecting flange on each rim.

7. A structure as defined in claim 4, wherein each core unit has atapered core pin spaced radially inwardly of each said core fingers fordefining the bore of the can tral tubular portion of the resultingspool, and wherein means is provided on each core pin to form an annularcavity for forming a circumferential flange extending integrally fromeach end of said central tubular portion of the spool.

8. A structure as defined in claim 4, wherein a tapered transfer pin issupported between said dies, and the dies have cavities forming, aroundsaid transfer pin, a sleeve part having runners extending to the barrelforming portion of the dies, whereby the resulting moulded spool bodycan be supported and moved upon separation of the dies and core unit.

9. In core structures for forming molded products of the kind described,a first core unit comprising a plurality of similar core elements which,when assembled, define a hollow body portion extending from a baseportion, each element including an outwardly tapered core fingerextending from the body portion within side limits of the body portion,a pair of shoulders on the body portion disposed adjacent opposedlateral sides of said finger; and a second core unit having fingersinterfitting with and snugly engaging the fingers of the first core unitand having shoulders, the shoulders of each unit being spaced from theextremities of the fingers of the other unit.

10. The core structure of claim 9 wherein the assembled fingers of saidunits define a circumferentially continuous bore throughout the majorportion of the length of said fingers.

11. In core structures for forming molded products of the kinddescribed, a first core unit comprising a plurality of similar coreelements which, when assembled, define a hollow body portion extendingfrom a base portion, each element including an outwardly tapered corefinger extending from the body portion within side limits of the bodyportion, a pair of shoulders on the body portion disposed adjacentopposed lateral sides of said finger, a second core unit having a bodyportion, shoulders on said body portion, and fingers interfitting withand snugly engaging the fingers of the first core unit with outer endextremities of the fingers of each core unit spaced from the shouldersof body portions of adjacent core elements of the other core unit, theassembled fingers of the core units defining a circumferentiallycontinuous bore throughout the major portion of the length of saidfingers, a tapered side wall upon each lateral side of each finger, oneof said lateral sides having an inwardly facing shoulder extendinglongitudinally thereof, the other lateral side having an outwardlyfacing shoulder extending longitudinally thereof, and the longitudinalshoulders of eachfinger engagingthe longitudinal shoulders of twoadjacent fingers in firmly retaining the as; sembled fingers in positionto resist inward and outward radial pressures to which said fingers aresubjected.

12. The core structure of claim 11 wherein the longitudinal shoulders ofthe fingers are longitudinally inclined.

13. The core structure of claim 11 wherein the longitudinal shoulders ofthe fingers are longitudinally inclined and transversely rounded.

14. In a core structure of the kind described, first and second coreunits, each said unit comprising a group of circumferentially spaced,identical, integral, replaceable core elements; each core elementcomprising a base portion at the inner end portion thereof, anintermediate body portion having an outer end, and a core fingerextending from said outer end of the body portion and terminating in afree end; said base portion having means for supporting the core elementin association with the other core elements of the core unit; said bodyportion having a pair of shoulders on the outer end thereof disposedadjacent opposite lateral sides of the core finger; said core fingerbeing of arcuate cross section and having outer and inner opposedsurfaces that are tapered from the inner to the outer ends thereof, saidfinger having on opposite lateral sides thereof an inclined,longitudinal extending, transversely rounded shoulder, each said lateralside having a side Wall partially defined by said shoulder and taperedfrom the outer to the inner ends thereof, one of said shoulders facingoutwardly and the other facing inwardly; said base and body portions ofsaid group of core elements collectively forming circumferentiallycontinuous base and body portions, respectively, having a thr-oughbore;the core fingers of each core unit being adapted to interfit with thecore fingers of the other core unit to form a circumferentialycontinuous core, said core units being relatively movable so as todispose the free ends of the core fingers of each core unit close to butspaced from the shoulders on the body portions of the core elements ofthe opposite core unit; said interfitting core fingers being supportedby the engagement of the shoulders of one core finger with the adjoiningshoulders of a pair of opposite core fingers, the outwardly and inwardlyfacing shoulders of the core fingers of one core unit respectivelyengaging the inwardly and outwardly facing shoulders of the core fingersof the opposite core unit; and said interfitting core fingers defining acontinuous bore which communicates with said throughbore.

15. In a core structure of the kind described, first and second coreunits, each said unit comprising a group of circumferentially spaced,identical, integral core elements; each core element comprising a baseportion at the inner end portion thereof, an intermediate body portionhaving an outer end, and a core finger extending from said outer end ofthe body portion and terminating in a free end; said body portion havinga pair of shoulders on the outer end thereof disposed adjacent oppositelateral sides of the core finger; said core finger being tapered fromthe inner to the outer ends thereof, said finger having on oppositelateral sides thereof an inclined longitudinal extending shoulder, oneof said shoulders facing outwardly and the other facing inwardly; thecore fingers of the first core unit being adapted to interfit with thecore fingers of the second core unit to form a circumferentiallycontinuous core, said core units being relatively movable so as todispose .the free ends of the core fingers of each core unit close tobut spaced from the shoulders on the body portions of the core elementsof the other. core unit; said interfitting core fingers being supportedby the engagement of the shoulders of one core finger with the adjoiningshoulders of a pair of opposite core fingers, and the outwardly andinwardly facing shoulders of the core fingers of one core unitrespectively engaging the inwardly and outwardly facing shoulders of thecore fingers of the other core unit.

16. In a core structure of the kind described, first and second coreunits, each core unit comprising a group of circumferentially spacedcore elements, each of said elements comprising an inner base portion,an intermediate body portion having an outer end, and an outer corefinger of reduced cross section extending from said outer end of thebody portion and terminating in a firee end; said core finger beingtapered from the inner to the outer ends thereof, said finger having onopposite lateral sides thereof an inclined, longitudinal extendingshoulder; the core fingers of the first core unit being adapted tointerfit with the core fingers of the second core unit to form acircumfere'ntially continuous core, said core units being relativelymovable so as to dispose the freeends of; the core fingers of each coreunit close to but'spaced from the outer ends of the body portionsof thecore elements of the other core unit; and said inter-fitting corefingers being supported by the engagement of the shoulders of each corefinger with the adjoining shoulders of a pair of core fingers of theother core unit.

References Cited in the file of this patent UNITED STATES PATENTS16,166- Smith, Jr. Dec. 2, 1856 806,783 Dayton Dec. 12, 1905 2,266,887-McCoy' Dec. 23, 1941 2,439,506 Christian Apr. 13, 1948 2,541,923 HuxhanFeb. 13, 1951-

